Any medical device manufacturer developing new products comes across design verification and validation. They are essential stages during the design control of a new medical device. Design controls are a series of steps and processes during the development of a medical device that ensures that new devices are safe and fulfill user needs. They document to the regulatory authority that your device is thoroughly well-designed and tested vigorously to ensure its safety.
While the term "Design controls" is mainly used by the Food and Drug Administration, FDA, ISO 13485:2016 include the same principles in its section 7.3 Design and Development.
Though Design Verification and Design Validation sound deceptively similar, they are different processes. This guide will review the two approaches and give you some tips to avoid the most common pitfalls.
Design Verification
According to the FDA, design verification means confirming "…by examination and provision of objective evidence that specified requirements have been fulfilled."
Design verification ensures that your design output matches your design input. Essentially, you verify that you designed the device right and to the predetermined design specifications. Design verification is performed during device development and includes testing the entire system and any subsystems and units within the system.
Design verification typically includes product testing, but there are other officially approved verification activities, such as inspections or analyses.
Design verification is typically made up of five distinct steps:
1. Prep
Before you start, you must identify the best approach for your verification. This can include defining your outcomes and how you will measure them and considering how many resources and tools you will need for your verification.
2. Planning
Any design verification worth it's salt should be appropriately planned. This is a continuous step over your device's lifecycle, as the plan should be updated whenever there are changes to the design inputs.
3. Developing
This is where your device development begins!
4. Execution
You execute your meticulously planned tests and document your results. Any device defects should be resolved, resulting in new product releases. This is also where you create and document your traceability matrix to ensure all your design inputs have been identified, tested, and passed.
5. Reporting
You should always document your entire design verification process, resulting in a report at each phase of the verification that includes release reports, test results, and any issues discovered during the verification. The report should be reviewed, approved, and signed by relevant personnel after each verification phase.
Design Validation
According to the FDA, design validation is "…establishing by objective evidence that device specifications conform with user needs and intended use(s)."
On the other hand, design validation ensures that your manufactured device meets the intended use and user needs. Design validation is performed after device development and includes testing the entire system (finished product). Design validation typically includes product testing or clinical trials where you test the device under real-world conditions. As with verification, every step of the validation process must be documented and contained in a final report at the end of each validation phase. The report should include test protocols, execution records, test results, and any other activity performed during the validation phase. All reports must be reviewed, approved, and signed by relevant personnel.
Best tips for design verification and validation
It is perfectly possible to have a device that passes design verification but not design validation or vice versa. While they might seem similar, the two processes are not the same. They must be treated as two separate stages of the design controls and therefore require different best practices.
Design verification tips
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- Thoroughly consider your device's intended use and how to achieve it. Every step of the design input process should reflect the desired outcome of the finished product.
- Consider what the conditions around the use of your device will be. Will it be placed in an OR, beside a hospital bed, in someone's home? Does it need to move with the patient? All the logistics surrounding your device will help you define the design input.
- Make sure your design inputs are measurable/testable. You need to be able to verify your design inputs through testing or analyses to match them to your design output.
- Be clear and precise when writing your design inputs. Even the slightest hesitation or ambiguity can cause significant issues during the design verification testing. Spending a little extra time making sure everything is documented clearly beforehand is better.
Design validation tips
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- Devices used for design validation testing should be manufactured in the same production units used going forward. The same production environment, production line, drawing, and specifications should be used to ensure the validated device matches devices going to market.
- Clinical evaluation is an integral part of design validation. Devices should be tested under real-life conditions or simulated use (for example, mathematical modeling). End users should be involved in real-life testing to assess the device's design under real-life conditions. In your clinical evaluation, your device should be compared to other devices using similar technology and design.
- Labeling and packaging are also part of the design validation and should be tested.
You can also do some things to help yourself through the entire verification and validation phase, which are not directly related to the processes themselves, but to how they are managed.
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- Start planning and testing as early as possible. The sooner you can start planning and testing, the sooner you might identify technological or process issues that can become significant issues down the line.
- Standardize nomenclature to avoid ambiguity and misunderstandings between departments and personnel.
- Choose the right tools. You want tools you can customize to your method, process, and tools that make sense for your company and resources. There are many development methodologies to choose from, and whichever one you choose, make sure you select the right tools to go along with it.
Product and Verification and Validation updates
Verification and validation are not a static one-time process. Any time your device design changes, your verification and validation should also be updated. This can be due to post-market surveillance data, customer feedback, complaints, corrective or preventive actions (CAPAs), risk management updates, or any other loop that feeds into your device design. No matter when the change is made or how long your device has been on the market, you must revisit your verification and validation processes.
